Sliding door for vehicles
At present, sliding doors are increasingly used in vehicles, which doors, when opened, are arranged ' first to move outwards and thereafter laterally along the wall of the vehicle. The desired path of movement is usually obtained by means of guiding rails which are positioned near the upper and lower edge of the door and along which supporting members fixed to the door move. In winter conditions, however, the lower rails are easily frozen and cause functional disturbances which, especial¬ ly in train cars and coaches, constitute a serious dis¬ advantage. ■
Fl-patent No. 61.149 describes an arrangement in which a conventional lower rail has been replaced with another guiding rail which is positioned near the upper edge of the door and along which a guiding arm, forming an extension of the swinging arm acting on the upper part of the door, moves. This known sliding door has eliminated said freezing problems but it has still some disadvantages.
The second rail and the guiding arm with its rolls moving along the rail take up so much space longitudinally in the car that it is not always possible to arrange enough space.
In order to have the door opening high enough, the moving upper parts must be placed very close to each other which results in a risk for accidents; it is dif¬ ficult to protect the moving u-jper parts. The play between said rail and the roll moving therein causes rattle during the movement. The play also results in that the path of movement is not entirely controlled, but the guiding arm may, when moving, touch the corner of the door opening in the car. With double doors the sealing of the doors in the centre is made so that the doors press against the seals of each other end-
wise in the longitudinal direction of the car. This force is reduced by the friction between said rail and roll.
The object is to provide a new sliding door which is not liable to inconveniences caused by freezing and which at the same time eliminates the above-men¬ tioned disadvantages.
The present invention thus relates to a sliding door for vehicles, on the upper part of which door there is a guiding member which is arranged to move along a guiding rail extending along the side wall of the ve¬ hicle and which is connected to a drive means, prefer¬ ably to the piston rod of a drive cylinder, through two first swinging arms and two second swinging arms, where- by both the second arms are linked to the corresponding first arms and to the door, at the upper part and cor¬ respondingly at the lower part thereof, in order to direct a force substantially perpendicularly against the plane of the door when the door is in closed position. The sliding door in accordance with the invention is mainly characterized in that in order to change the door opening movement directed outwards by the first and second swinging arms into a movement along the side wall of the vehicle a guiding linkage is connected to at least one of the second swinging arms which linkage comprises an extension integral with said second swinging arm and' projecting beyond the link between the first and the second arm, and a hereto linked third swinging arm pro¬ vided with a fixed pivot bearing. Since the link between said extension and the third arm moves along a circular path, a movement is achieved which is practically playless and transferable to the other end of the door by means of a rod extending along the door, as such in the same manner as described in Fl-patent No. 61,149.
In accordance with the invention it is possible to
position all the guiding members required by the sliding door inside the car and because of this the- door func¬ tions reliably in hard winter conditions and the door, when opened, is not pushed out more than is necessary
<*. 5 ' in order to permit a lateral movement. Further, the guiding linkage of the door can be positioned in the most preferable place from the viewpoint of security and use a space respectively, e.g., at the lower part of the door under the first step. 10 In the following the invention is described in more detail with reference to the enclosed schematic drawing. Figure 1 shows a sliding door seen from above when the door is closed.
Figure 2 is a view in the direction of arrow A of 15 figure 1.
Figure 3 is a view in the direction of arrow B of figure 1.
Figures 4 to 6 correspondingly show the situation when the door is open. 20 In the drawing, the door itself is designated with reference numeral 1 and the outer wall of the vehicle with numeral 2. Beside the upper edge of the door is a guiding rail 3 which is preferably arranged to a sup¬ porting structure 4 attached to the outer wall 2 of the 25 vehicle, figures 3 and 6. To the front edge of the upper part of the door, from which the door is opened, a sup¬ porting or guiding member is fixed which comprises an arm 5 and a roll 6 or similar and which moves along the rail 3 guiding the front edge of the door to move in the 30 desired manner.
As the drive means of the door there is a drive cylinder 7 which operates, e.g., pneumatically. The piston rod 8 of the cylinder is linked to an arm 9 which at its other end is fixedly connected to a rotatable 35 rod 10 which at its upper end is mounted in the supporting structure 4 and at its lower end in the frame 11 of the
vehicle. To the rotatable rod 10, at the level of the upper and lower ends of the door, arms 12 and 13 are fixedly connected which through links 14 and 15 are connected to arms 16 and 17 which in their turn are joined to the door 1 through bearings 18 and 19. The arms 16 and 17 are interconnected with each other through a vertical rod 20 extending alond the door 1. The arms 12 and 13 are hereafter called the first swinging arms and the arms 16 and 17 the second swinging arms. When the piston rod 8 pushes outwards, the arms 9 as well as 12 and 13 turn with the rod 10 and the arms 16 and 17 push the door 1 outwards. The rail 3 guides by means of the supporting member 5, 6 the front edge 1a of the door into the desired movement, separate guiding is needed in order to get, also for the rear edge 16, the desired movement along the outer wall of the vehicle.
In accordance with the invention the guiding of the rear edge 1b of the door, and thereby a controlled guiding of the whole door, is obtained thus that at least one of the second swinging arms 16 and 17, on the draw¬ ing the arm 17 acting on the lower edge of the door, is provided with a fixed extension 21 projecting beyond the link 15, which extension according to the drawing can be formed in one piece with the swinging arm 17 and which at the end is connected through a link 22 to a third swinging arm 23 which in its turn is linked to the frame 11 of the vehicle. This link is designated with refer¬ ence numeral 24 on the drawing. When the rod 10 turns clockwise from the position according to figure 1 , the link 15 moves along an arc 25 and the link 22, or the end of the extension 21, along an arc 26, the last mentioned guided movement causes the arm 17 and, by means of the rod 20, also the arm 16 to turn at the link 15 and correspondingly at the link 14 so that the bearings 18 and 19 between the door 1 and the
arms 16 and 17 move in the direction of the wall of the vehicle along a path 27.
The form of the important path of movement 27 depends primarily on the length of the extension 21 and ' the third swinging arm 23 and on the position of the link 24, but naturally all parts of the sliding door construction have their given effect. One attains best the desired result by experimenting, sometime beginning with, e.g., the position of the rotating rod 10 which position defines the length of the first swinging arms 12 and 13. On the drawing, especially in figures 1 and 4, an attempt has been made to show an embodiment oper¬ ating in practice as regards its proportions on a scale about 1:10. The guiding linkage 21, 23 is preferably posi¬ tioned under the step 28 in the manner shown on the drawing, but an upper position is naturally also poss¬ ible, whereat the arm 23 would be mounted, e.g., on the upper supporting structure 4. By using a lower as well as an upper guiding linkage the rod 20 can be left out.
OMPI ^ NATlO